Strong energy dependence of the optical potential for /sup 32/S+/sup 58,64/Ni near the Coulomb barrier

The elastic scattering of /sup 32/S+ /sup 58,64/Ni was measured at sulfur beam energies of 82, 88, 91, 93, 98, 102.5, 108, and 150 MeV. Evidence is found for a marked energy dependence of the optical potential at the strong-absorption radii around the Coulomb barrier, in good agreement with parallel information extracted from the fusion cross sections for the same systems.